- 1/4 cup plain nonfat yogurt
- 2 tablespoons (packed) chopped fresh cilantro
- 1/2 small garlic clove, minced
- Nonstick vegetable oil spray
- 1 1/2 pounds yams (red-skinned sweet potatoes), peeled, cut into 1-inch-thick slices
- 3 3/4 cups (or more) low-fat (1%) milk
- 1 1/2 teaspoons ground coriander
- Mix yogurt, cilantro and garlic in small bowl. Cover and refrigerate.
- Preheat oven to 400°F. Spray large baking sheet (preferably nonstick) with vegetable oil spray. Arrange yams in single layer on prepared baking sheet. Roast until bottom sides of yam slices are brown, about 20 minutes. Turn yams over and roast until tender, about 15 minutes longer.
- Meanwhile, combine 2 cups milk and coriander in heavy medium saucepan. Bring to simmer. Reduce heat to very low; cover and cook 10 minutes. Remove from heat.
- Combine yams and milk mixture in processor. Puree until smooth. Return to same saucepan. Stir in remaining 13/4 cups milk and bring to simmer, thinning with more milk, if desired. Season to taste with salt and pepper. (Yogurt mixture and soup can be prepared 1 day ahead. Cover separately and refrigerate. Rewarm soup over medium heat before continuing.)
- Ladle soup into bowls. Swirl 1 tablespoonful of yogurt mixture into each. per serving.